1. Field of the Invention
The invention relates to a transmission for wind generators of the type having a rotor connected to at least one generator via a multi-stage transmission and a spur gear.
2. Description of the Related Art
DE 199 17 605, to which U.S. Pat. No. 6,420,808 corresponds, shows a shaft-mounted transmission for wind generators. This transmission is mounted on a rotor shaft supported in the tower of a wind power plant and is supported on the shaft via two bearings. The transmission housing is attached to the tower of the plant by means of torque arms.
The rotor shaft is driven at the end remote from the transmission by a rotor head with wind blades and passes the driving torque into the transmission via an annular gear. The annular gear is secured on the rotor shaft by means of an annular gear carrier and drives the planetary gears of a first planetary stage. The shafts, which are mounted in a manner fixed relative to the housing, each carry a further planetary gear of a second planetary gear stage, which drives the shaft of a spur gear via a sun gear. A pinion that meshes with this spur gear drives the generator via another shaft. Such plants are assembled from a large number of components in an involved process and result in a large overall length.
Taking this as a starting point, the object of the invention is to create a more compact plant that is of shorter and lighter construction and can be assembled more easily.
According to the invention, the rotor is supported in the transmission housing and has an annular gear carrier with an annular gear fixed thereto, the annular gear forming part of the transmission.
Through the elimination, in accordance with the invention, of the rotor shaft together with its bearing arrangement in the tower, a particularly advantageous shorter construction of the plant is obtained.
This furthermore offers the advantageous opportunity to shorten the machine housing, and the reduced number of components means that the weight of the top of tower is lower, thus allowing the supporting structure to be of smaller dimensions.
By virtue of the construction according to the invention and the elimination of a joint between the transmission and the rotor shaft, assembly is considerably simplified, thereby advantageously shortening the time for assembly.
Thanks to uncomplicated extension of the rotor, the transmission housing and the annular gear carrier, the span of the rotor bearing arrangement can be extended and thus advantageously adapted in a simple and optimum manner to the external force conditions.
The sliding-contact bearings provided according to the invention can advantageously be raised hydrostatically when starting the rotor and transferred to hydrodynamic operation through a simple control operation as the speed increases.
A crowned toothed coupling between the annular gear carrier and the annular gear itself allows the toothing of the annular gear to center itself on the planetary gears.
By virtue of the advantageous integration of the rotor with its bearing arrangement into the transmission, the transmission housing also supports the rotor head with the blades, thereby making it possible to dispense with additional supporting or bearing structures.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.